Grease on disk break do they need to be replaced?

I think I got some grease of my rear disk break because when I was riding to day it wasn't really stopping at all and i checked the disk and there was some grease on it. They are avid code 5's if that matters. It could be that i need new pads just because they are getting worn, but lat time I rode it didn't seem like they were bad at all. But I believe it is the grease so is it something where I can just let them sit a few days and they will be fine or do I need new pads?